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Dither is low level noise that is added to a digital signal when converting from higher resolution(e.g. 24 bit) to lower resolution(e.g. 16 bit).
The slight randomizing effect of the noise helps to preserve more details in the signal than would be present if the signal were simply truncated to the lower bit rate. Noise-shaped dither(such as Apogee UV-22 or Sony
Super Bit Mapping) places the noise in a part of the frequency spectrum that is latest obvious to the ear. Most mastering labs place a high priority on having various high quality noise-shaped dithering algorithms
available in order to encode the highest possible resolution.
Jitter is type of distortion that occurs when the digital bits arriving at the digital to analog converter(DAC) are not perfectly evenly
spaced. The DAC translates the digital bits into an analog waveform as they arrive and if there is a variation in the timing of their arrival, distortion will be introduced into the analog signal. This is why
digital clones can sound different from each other. The data may be the same but if there is any variation in the timing of the data stream the resulting(analog) sound will be subtly different.
Analog to Digital, refers to the conversation of analog sound waves to digital binary information, as in a DAT(Digital Audio Tape) Recorder. This
is also called "Digitization"of an analog source into digital format.
- CAPACITY:(DATA CAPACITY):
The amount of data which can be stored on a given type of media, such as CD, Syquest removable, or floppy disc. The capacity of a CD is 654.7
Megabyte(Mb), which is 335250 2k Sectors. This is equivalent to 74 minutes 30 seconds. The track pitch and speed of rotation affect the amount of data than can be stored on a CD. It is possible to
record more data on a CD than the "normal" capacity, but it isn't recommended. SyQuest capacities now range from 44 megabytes to 270 megabytes
.
Compact Disc Digital Audio. The CD which was introduced in 1983 is an audio storage device that contains up to 74 minutes of high quality stereo
sound. Only one side of a CD contains the audio material stored on the CE in a spiral from the inner edge to the outer edge. CD-R: A one-write recordable compact disc that has the index points set manually. A
PM-CD, however, has frame-accurate index points.
Compact Disc Read Only Memory. A special format of the CD that allows the storage of text, graphics, audio and video. The CD-ROM is similar
to the CD-DA(Digital Audio), but the information is stored differently. An audio CD player can't play CD-ROMs, but CD-ROM players (such as the Apple CD-ROM players) can play CD-DA discs and can be connected to an
external amplifier and/or headphone. The CD-ROM player is usually plugged into one of the computer's expansion slots or he computer's SCSI(Small Computer System Interface) port. A CD-ROM can hold 650 Mb of data, which
is equivalent to about 250,000 pages of text.
The machine(hardware) used to read data from a CD-ROM dics.
Data Compression is a process that reduces the size of a file by "eliminating" any redundant data. Many different schemes of compression
exist for audio, computer data, video etc. Compressing a file saves storage space and allows for faster transmission of data. Decompression is the reverse process to restore data to its original form.
Digital Audio Tape(also R-DAT). DAT is a system designed for recording and reading digital data using special tape cassette. DAT can
be used to store over one gigabyte of computer data and audio also can be used as a master source medium for sending your audio to duplication plants. DATs can be recorded at either 44.1 kHz, however it is
important to note that all DATs recorded at 48 kHz will need to be digitally converted to 44.1 kHz.
The process by which information is converted from one form to another. For example, analog audio signals are "converted" to digital
when recorded onto a DAT. The process also refers to the sampling rate conversion that sometimes occurs in the mastering process, where a DAT sampled @ 48 kHz is converted to 44.1 kHz.
A combination of Digital and Analog. Source material is input digitally onto a digital running master, then output at high speed onto the
analog cassette tape. As close to CD quality as a cassette can be.
Any audio source that has been converted to a digital form. CD-quality audio is usually the standard that it refers to, that is audio sampled at
16-bit resolution and 44.1 kHz sample rate. This standard refers to the Red Book standard in the audio industry.
Error Correction Code. Usually found in the hard ware of computers, CD audio players and DAT machines, ECC allows that particular machine to
reconstruct small errors or missing data in files. EDC, Error Detection Code, allows that particular machine to detect small errors or missing data in files.
The process by which a metal master(or "father") disc is created by electroforming nickel onto the glass master. The father is then used to
create a "mother" and from the mother, a "stamper" is created to be used in the injection molding machine to create the CD(or used in the press to press vinyl record).
The first step in the CD replication process. A large glass disc which is
coated with a photosensitive material is bombarded with laser light to encode the data. The glass master is then exposed and developed to create a "father".
How data is organized upon a give medium. It also refers to the actual medium(DAT, CD, VHS etc.)
When referring to video, the information(or time) required, for one complete picture to be viewed. In North America, there are several
video frame rate standards 30 frames per second(fps), 29.97 fps. Film has a frame rate of 24 fps. CD-Audio stores information in frames as well. There are 75 frames per second on a audio CDs. However the CD
frames and video frames are not related.
The hard disk volume which contains the data for a CD-ROM. The disk image is the written to a recordable CD or Pre Master CD (PM-CD).
Index randomly accessible points on a CD. Up to 99 separate index points(or "tracks") can ve encoded on a CD. Within each track, however and additional 99 sub-index points can e encoded.
A CD-ROM standard created by the International Standards Organization which defines a layout structure for CD-ROM. Supported by PC and UNIX systems
.
Where the Table of Contents(TOC) is recorded on a CD. Contains the track listing and other pertinent information about the track. It is found
at the beginning of the CD. Also, the spiral groove at the beginning of a vinyl record.
A buffer area after the last track on a CD. When the lead out code is read by the CD player it will return to the beginning of track#1 or it will
stop playing depending on the programming. Also the spiral groove leading into the center of a vinyl record.
Musical Instrument Digital Interface, an information protocol which allows synthesizers which abide by the MIDI standards to communicate
data with each other. MIDI information can be stored as a MIDI file on disk which can then be utilized in a multimedia program.
National Television Systems Committee, the color television standard for the United States, Canada Japan, Mexico, Taiwan and others of 30
frames per second for the video signal.
Phase Alternation Line. the color television standard used in most Europe(except France which is SECAM) and south America of 25
frames per second.
Pulse Code Modulation, one of the standard methods for encoding audio in a digital format sampled at 44.1 kHz.
The information on a CD surface. By exposing a photosensitive layer on a glass master to laser light, and then washing away the exposed
material, pits are formed. The track is written in a spiral from the inside of the disc to the outer edge.
Digitally encoded information on a CD which controls information read out such as indexing and spacing.
The area of the disc where the information(program) is stored.
A 1 kHz tone should last approximately 30 seconds at minus 14db on DAT level meters. This is provided to assist mastering engineers to
calibrate their machines to your original recording machines.
Time code, a video time-code scheme used to mark the hours, minutes and frames of a video program, however widely used in audio recording industry.
Universal Product Codes(UPC), a series of vertical lines and numbers which are unique to each individual product and identify it.
Source material required for the CD or cassette labels and the corresponding packaging. These include photographs, rendered artwork,
final firm, fonts etc.
A step in the CD replication process where melted plastic is injected into a mold(which contains the "stamper") under pressure, cooled and
removed as a solid, clear plastic disc. The formation that was on the stamper has now been transferred to the plastic disc.
Printed cassette insert which when viewed from the side resembles the letter "J".
The standard, universally accepted plastic CD case.
The printing on the actual CD. Accomplished by screen, pad or offset printing methods. Also refers to the paper label affixed to a vinyl
record.
The standard universally accepted plastic cassette case. |
